Abstract IgE-mediated food allergies have become a major public health concern, now estimated to affect 6-8% of children under 4 years old and 4% of adults in the US. Approximately 200,000 emergency hospital visits are caused from allergic reactions to foods annually, with at least 150 fatalities resulting from anaphylaxis. The overall economic cost of food allergies in the US is estimated at $25 billion. There are currently no FDA-approved treatments for food allergies and as such the only options available to allergic individuals are strict dietary avoidance of the allergen and emergency treatment with epinephrine if a reaction occurs. Allergic reactions to tree nuts, including walnuts and pecans, often result in life-threatening anaphylactic reactions and, along with peanut, are the primary foods known to trigger fatal reactions. Accidental exposures to nut allergens are common, since nuts can be hidden in foods or contaminate foods served in restaurants and cafeterias. Tree nut allergies are rarely outgrown and have increased in prevalence over the past decade and are now estimated to affect greater than 1% of the US population. While some treatments, including oral and epicutaneous immunotherapies, are being investigated for peanut allergies, there are no rigorous studies being conducted in subjects with tree nut allergies. Unfortunately, the benefits of these desensitization therapies are typically mild to moderate and in most cases are short-lived. Therapeutic vaccination is a new and exciting potential treatment option for allergies that require a considerably abbreviated treatment schedule and may have more profound and longer-lasting effects. Most therapeutic vaccination approaches being tested seek to reduce the symptoms caused by Th2-driven IgE by shifting the anti-allergen immune responses toward a Th1 phenotype characterized by IgG antibodies. Genetic vaccination approaches are among the most promising of the therapeutic vaccination approaches being investigated. Three main types of seed storage proteins (legumins, vicilins, and 2S albumins) bind IgE and cause allergic symptoms to walnuts and pecans. Targeting these nut proteins represents a sound strategy for therapeutic vaccination. Under this phase I SBIR, we intend to test an adjuvanted multi-valent walnut/pecan therapeutic DNA vaccine co-expressing a Th1 polarizing genetic adjuvant in a pre-clinical mouse model of walnut and pecan allergies. If our vaccine can be used to treat walnut and pecan allergic mice to successfully prevent anaphylaxis upon oral challenge, we will continue development under phase II by performing toxicology studies and beginning GMP manufacturing of the vaccine to support an IND application. 2